The Administrative and Biostatistics Core will: promote high quality collaborative research in cerebral vascular disease by providing a supportive academic environment in which investigators can carry out scientific projects, facilitate the interaction of projects and cores, oversee the administration and financial aspects of the knowledge towards an understanding of the mechanisms and management of cerebrovascular disease. The role of the Biostatistics Core in the Stroke Project is to support the clinical and laboratory based research. This includes a high-level data management, collaboration with investigators in the design and conduct of research studies, statistical modeling, hypothesis formulation and data analyses. There are four major activities: 1) consultation and collaboration in the planning, conduct, analysis and reporting of the pilot clinical trial; 2) consultation and collaboration with research investigators in developing an MRI based model to stage ischemic tissue and to integrate MRI measurements into the evaluation of therapeutic intervention with a platelet aggregation inhibitor and thrombolysis with rtPA; 3) evaluation of the prognostic significance of risk factors and MRI biological markers, based on the presence/absence of quantitative levels to identify non-response subjects, 4) coordination on project conduct, responsibility for data management and data quality.